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Old September 22, 2021, 10:34 PM   #51
Metal god
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When I hear that phrase I consider it hyperbole, never to be taken literally. We use phrases like that in our normal everyday conversation all the time and no one gets uptight about it.

I may refer to one of my grandkids as "sharp as a tack". Or "fast as lightning". No, they aren't literally as fast as lightning, but people get the idea.

If someone were to say "Sub MOA, all day long" I take it to mean they have a very accurate rifle. No more, no less.
I think that's a good answer .

I've used the term and meant it . The thing is in that statement I mean the rifle can do it and not necessarily me doing it . If I shoot 15 out of 20 five shot groups sub MOA and the other 5 groups right at MOA in a 2hr session . I will call that a sub moa all day rifle cus I truly believe it would have done that with a better shooter behind the trigger . I think Bart B in the past has pointed out Sierra test barrels do that all week and month long . A lot of guns are able to do sub MOA all day long . The hard part is finding someone that can shoot as well as the rifle to prove it ;-)
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Old September 25, 2021, 07:46 AM   #52
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Metal_god, first off, I have to hand it to you for your signature at end of your posts…. “If Jesus had a gun, he’d probably still be alive!” I about come unglued from that one. I am a church-going practicing Christian myself, but I am of the thought that NO ONE can resist the truth wrapped in a good joke. Plus, if you can’t laugh at your own thoughts and beliefs, you don’t deserve to have them…

Brass taxes.. I have heard that factory guns adverts claim they can get sub-MOA three shot groups all day long. I can read that until I am blue in the face. And it is probably true. If you practice proper shooting techniques, anything is possible. Heck even with a “Minute of Deer” rifle, you could probably get a ragged hole at 100 yards if you really paid attention.

Problem I find is, from bargain hunting rifles for kids or first timer’s to pricey long range darlings, it ALL comes down to human error, no?? I see it two basic ways, please augment my points as you all see fit. Or debate me. Either way, information is shared.

Number A: Factory could be having a banner day, action rails are straight and true, heat treatment is perfect, all the machining is epic perfect. Barrel mounted perfectly true, everything just right from factory. Some noob buys it, takes it to range and just doesn’t quite know all the techniques and basics and can’t hit the broad side of a cow with a snow shovel…. Lackluster groupings. But on other side of that, if you have the scenario mentioned above, and a great shooter, you could be driving tacks over a mile away.

Number B: Polar opposite…. Factory has what my father calls “a bad union day” and the guy is on coffee break more than he works, making grievances and not getting any parts made correctly. Barrel on about as straight as a Virginia fence, rails twisted, heat treatment is junk. You essentially have a boat anchor, but you have a fine shooter that’s able to adapt and make some shots. (However unlikely this may seem to be, granted.). But you could also have this scenario, and a bubba shooter, and probably never even put pills on paper at 100 inches let alone 100 yards.

Thoughts??
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Old September 25, 2021, 07:48 AM   #53
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Another thing I have read is barrel makers claiming sub-MOA all day long. I just picked up a barrel from Carbon6, and that is their claim, but they CLEARLY mark in large print on their website, “May not happen out of the box. With proper load development this is absolutely possible.”

I plan on developing some loads from once fired brass, and I hope that I can really do some damage with this thing once its finished.

With a fine gunsmith putting the pipe on, and truing the action as they should. I have no doubt in my mind that precision and accuracy can be squeezed out like that. For sure.
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Old September 25, 2021, 08:51 AM   #54
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To me it means every one of 10 shots will be sub-moa

As a rule-of-thumb statistics thing, a sample that is the square root of the population is sufficient. In other words, 10 shots is most likely a good representation of what 100 shots will look like. The more shots you take, the more likely your claim.

I’ve seen fellas claim the have a ‘sub moa rifle’ because the third group of three they shot was sub-moa.

To me, that’s just cherry-picking the data. They shot 9, and could not make it sub moa. Three isn’t a big enough sample to have high reliability. They got lucky. Minute of Deer? Sure, but not sub moa.

All day long? Give me an hour between shots? Sure.
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Old September 25, 2021, 12:31 PM   #55
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As a rule-of-thumb statistics thing, a sample that is the square root of the population is sufficient. In other words, 10 shots is most likely a good representation of what 100 shots will look like. The more shots you take, the more likely your claim.
Awesome that means these rifles are sub moa all day long



And this rifle



and this rifle



and this 5 shot group must be close enough based on the other groups above , I'm clearly good enough to shoot 5 more under MOA in that group ...... err wait what ????



LOL . No , I can't shoot sub moa with any of those rifles all day long but I have shot many MANY 10 shot sub moa groups with multiple rifles and hand loads . Once I came dame close to sub 1/2 MOA 10 shot group . FWIW these are all from factory rifles or AR home builds/assemblies .

Interestingly enough , because I've not been shooting much rifle in the last few years . I have a hard time shooting sub moa with any of my rifles right now . I was shooting once or twice a week when I shot the above groups , Now I shoot rifle for accuracy once or twice a year You really do need to keep up with your skills to shoot well ( at least I do ) I mean I can still shoot pretty good but sub MOA all day long is not even a consideration right now .
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Old September 25, 2021, 12:46 PM   #56
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Wait there's more , I'm SOOO good I can shoot 2 sub moa groups in the same 10 shot string haha

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Old September 25, 2021, 01:56 PM   #57
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It's just an expression. It's not meant to be taken literally. GEEZ!!!
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Old September 25, 2021, 07:54 PM   #58
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no chance at 3/8 MOA much less 1 MOA because they don’t have the training.
Less training more skill or the time taken to learn how to shoot.

I never had none of that thar training stuff. Now gratned, my self built targets guns may not be real guns (lord knows you would not want to take one hunting) but they will shoot Sub 5/8 MOA let alone 1 MOA.

That said, on bad days I am lucky to shoot 1 MOA. But that is me not the gun.

So yea, Sub MOA all day long (for me that is 5 hours of so of shooting 150 rounds.

Often there are test loads that do not shoot it, but if I use one of the go too loads or am shooting developed loads, it will do it.

I tried some factory match rounds in 308 and no they did not shoot sub MOA. But that is also my worst shooting gun. More a 3/4 MOA with hand loads

Caveat is I do let the barrels cool down, either via cease fire and or combo of lower temp or just rack the gun and shoot another one for a while.
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Old September 25, 2021, 10:27 PM   #59
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My built target rifle will consistently put bullets through the same hole without egg shaping the hole at 100 yards but I can't do more than three shots without messing it up. Will it shoot sub minute of angle all day long? Probably. Can I? Nope.
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Old September 26, 2021, 07:36 AM   #60
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I brought out my Mossberg 800B .243 yesterday (It was my great uncle's gun, I got it sometime in the mid 90s, haven't shot it in about twenty years).

Ran a bunch of different loads through it, between me and the gun I was averaging about 1.75 MOA. One group out of about ten looked beautiful, all five rounds touching. I had shot a few other groups with that exact same load without that result. Was it me? Most likely. Was it the rifle? Not nearly as much as me. It would have been super easy to just post that one picture and say that is what my rifle and I can do, "all day long" when in fact that was realistically just the highlight group of about ten different groups.
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Old September 26, 2021, 08:38 AM   #61
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Originally Posted by stagpanther View Post
I've heard and read this quote a thousand times over decades--my question is has such a rifle ever truly existed? Seems impossible to me.
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Old September 27, 2021, 01:39 PM   #62
Metal god
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I had shot a few other groups with that exact same load without that result. Was it me? Most likely. Was it the rifle? Not nearly as much as me. It would have been super easy to just post that one picture and say that is what my rifle and I can do, "all day long" when in fact that was realistically just the highlight group of about ten different groups.
Yep that's why I posted those groups above . I've shoot 10 shot sub moa groups more then I would have thought I could but that does not mean I do it all day long . As load development progresses in 5 shot group increments , once I've settled on a bullet , powder , charge weight and seating depth that I think is my best combo . I then go out and shoot 2 o 3 ten shot groups with that load to confirm it is actually good . That is when I've shot those ten shot groups above . I generally only shoot 5 shot groups except in final testing . If I can shoot 10 shots in a row 3 to 5 seconds apart at sub moa , I call that load gtg . That is not to say every 5 or 10 shot group with that load will be sub moa but is a good indicator the load is good .

I don't believe because I shot a 10 shot sub moa group that is a good sample of what I'll get with 100 shots . The problem with groups is that they can only get bigger the more shots you fire . It's not like that 1 moa 10 shot group will ever be a 3/4 moa group if you keep shooting . The best I've ever done was a 16 shot sub moa group at 100yds . I was shooting one of those test loads once and shot 10 at sub moa so I just kept loading and shooting to see how many I could shoot sub moa . The 17th shot was WAY high and to the right by about 1.5in from the rest of the group . I wish I would have kept shooting or later investigated what caused that shot to miss so badly . It felt good and was not called high right it just went there and I just stopped shooting and called it a good load .
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Old September 27, 2021, 03:25 PM   #63
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Originally Posted by stinkypete
As a rule-of-thumb statistics thing, a sample that is the square root of the population is sufficient. In other words, 10 shots is most likely a good representation of what 100 shots will look like. The more shots you take, the more likely your claim.
Unfortunately, that doesn't work out very well because, on average, groups always get bigger with sample size because the more shots you fire, the more chances you give less probable results to appear, so the more likely it is you will get one. For example, you wouldn't expect a 2-shot group to be representative of your typical 4-shot groups. You'd expect the latter to be bigger. The stats say it will be 1.8 times bigger, on average. So the square root rule has problems in small sample sizes. My old company's manufacturing statistician said the sample should be the square root of the total number of items in a run (the population) or they should be thirty, whichever is larger. This is for the purpose of estimating population standard deviations and mean value, though, and not for estimating the extreme spread, which always has a random element.

The first plot below shows how much extreme spread grows with sample size for the same SD. For example, for a 9-shot group, the ES is expected to be about 3 times the SD on average. For a 27-shot group, ES is expected to be about 4 times the SD on average. And for a 95-shot group, ES is expected to be about 5 times SD on average.

Below that plot is another that shows the 95% confidence limits for sample size. You can see in that lower plot that a sample of 2 has very high upper and lower limits that subsequent samples of 2 might turn out to have as the difference in extreme spread between the two samples. The closer those lines are to the average, the smaller the difference your next sample that same size is likely to have. You can also see that by the time you get to 30 samples, the spread is no longer converging very fast.

The bottom plot also shows, though, that a sample of ten is fine as long as you are satisfied with 95% confidence limits in expected variation from one sample to the next that fall within those plotted limits. For ten, it's within about ±20%. That's part of the fun with this stuff. You get to decide how certain you need to be. But if someone tells me they will build me a 3/8 moa rifle, I will want to know for what group size and confidence level and at what range I can expect it to shoot 3/8 moa. Otherwise, even for a machine rest, the number is meaningless. For example, we can all stay within 3/8 moa group diameter with any gun for a 1-shot "group".



Attached Images
File Type: gif Confidence Limits v Sample Size.gif (21.9 KB, 148 views)
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Old September 28, 2021, 07:39 AM   #64
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One thing that I found interesting is the difference in effect between group size and group placement.
In the series of target pictures posted above there are two which illustrate this. There is a 10 shot group of 0.85” and another of 0.97”.
The smaller group scores 88. The larger group is a 95.
Just an observation.
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Old September 28, 2021, 08:07 AM   #65
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Just means they aren't trying hard enough.
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Old September 29, 2021, 05:02 AM   #66
Lt.Nick
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I can shot sub moa groups with all my rifles. If I give one to my father to shoot. His groups are almost always smaller. Im a very good shooter, dad is better. I think the comment about shooter being up to task, is spot on.
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Old September 29, 2021, 10:13 AM   #67
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Originally Posted by darkgael
One thing that I found interesting is the difference in effect between group size and group placement.
It's one of the basic problems with evaluating POI. Not only do group sizes vary, so does their center location wander around, though it wanders less than extreme spread (group diameter). This is because extreme spread (group size) is based only on the two holes, while the group center is influenced by all the holes in the paper. It turns out that the standard deviation of how much the group wanders around is equal to a number called the standard error. To find it, you divide the standard deviation of the whole sample by the square root of the size of the sample. So, for those 10-shot groups, you could expect something like the SD/3.16 is the amount the mean would wander around.
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Old September 29, 2021, 10:36 AM   #68
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As to group placement in those groups above . All those groups are either different loads or different rifles . When testing a load I don’t care the POI as long as my POA is consistent. The reason the POI is not centered on the target is because any given rifle I have is sighted in using one specific load and those loads above ain’t it . I rarely shoot for tight groups once a load is set and rifle is sighted in for that load . At that point I’m more of a hit the target type of shooter rather then a bunch of tiny little groups shooter .
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Old September 29, 2021, 11:52 AM   #69
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Originally Posted by Metal god View Post
As to group placement in those groups above . All those groups are either different loads or different rifles . When testing a load I don’t care the POI as long as my POA is consistent. The reason the POI is not centered on the target is because any given rifle I have is sighted in using one specific load and those loads above ain’t it . I rarely shoot for tight groups once a load is set and rifle is sighted in for that load . At that point I’m more of a hit the target type of shooter rather then a bunch of tiny little groups shooter .
Same here. One rifle, one load, zeroed at 200 yards from the bench. Plenty of Thump and -1 to 1 1/2 MOA is all I'm looking for from a hunting load. If it holds that to 300-350, I'll use that load indefinitely.

From then on, it's pick an object/animal and hit it from field positions.
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Old September 29, 2021, 10:12 PM   #70
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I think all the NRA's high power or smallbore rifle competitors classified master or high master shoot rifle and ammo testing under MOA. Often under half MOA.

Last edited by Bart B.; September 29, 2021 at 10:18 PM.
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